Macbeth is a character with a conscious and knows what will happen if he goes over to the dark side. Knowledge of this is one thing but the experience is somethng else entirely.

In Act 5, scene 5, Seyton informs Macbeth of the death of his wife. Macbeth's response, the "Tomorrow" speech, is perhaps the best example.

As a human being, Macbeth has sunk as far as any human being can go. The killing of the defenseless king seemed to whet his appetite for blood. Banquo's death was easier since he sent assasins as he also did with Macduff's wife and children.

In the "Tomorrow" speech, he realizes the futility of it all. The final result is it was all for nothing.

Do I feel he doesn't deserve what he gets? No, he does derseve it. He makes the decisions that lead to his downfall of his own free will. He knew what would happen to him. "Blood will have blood, they say."